>> find me a voter for voted for mccain four years ago and now says obama. it's a small segment of the population. this is the kind of message. it's an invitation to the former obama voters, the one-time obama voters who may be supporting him right now, on the fence right now, to say join us on the other side, you don't have to hate the guy, that he's the wrong direction for the country, we're giving up on him, moving the other direction. it's a powerful message, something the romney campaign would have liked to tap into a few months ago. >> greta: michael? >> how are the people in the middle, willing to vote for either party, not strong partisan, how are they going to break at the end of the day? they could decide it. >> the romney party will break overwhelming against obama. if he hasn't closed the deal yet, they'll get the voters. the cautionary note in 2004, john kerry was banking on a similar dynamic. he was hoping a lot of people that voted for george w. bush would say, i don't like the things worked out, i'll go with kerry. they split down the middle,